Dicyclopentadiene polymer product

ABSTRACT

A novel polymer product comprised of polymerized units of dicyclopentadiene and method of making the same as disclosed.

This application is a continuation-in-part of application Ser. No.672,424, filed Nov. 16, 1984, now U.S. Pat. No. 4,584,425, which was acontinuation-in-part of application Ser. No. 497,918, filed May 25,1983, now U.S. Pat. No. 4,507,453, which was a continuation-in-part ofapplication Ser. No. 342,455, filed Jan. 25, 1982, now abandoned.

BACKGROUND OF THE INVENTION

This invention relates to novel polymer product compositions. Inparticular, it relates to a crosslinked, high modulus, high impactstrength, thermoset polymer of dicyclopentadiene units which is formedvia a metathesis-catalyst system.

A good thermoset polymer should meet at least two criteria. It shouldhave desirable physical properties and it should lend itself to easysynthesis and forming. Among the most desirable physical properties formany polymers is a combination of high impact strength and high modulus.It is desirable that good impact strength be combined with a modulus ofat least about 150,000 psi at ambient temperature. Thermoset polymerswith high impact strength and high modulus find useful applications asengineering plastics in such articles of manufacture as automobiles,appliances and sports equipment. Among the critical factors in thesynthesis and forming of a thermoset polymer are the conditions and timerequired to make the polymer set up or gel. Many thermoset polymersrequire considerable time, elevated temperature and pressure, oradditional steps after the reactants are mixed before the setting iscomplete.

Not only is it desirable that the thermoset polymer have high impactstrength, but it is also desirable that it be easily synthesized andformed. A reaction injection molding process achieves this second goalby in-mold polymerization. The process involves the mixing of two ormore low viscosity reactive streams. The combined streams are theninjected into a mold where they quickly set up into a solid infusiblemass. For a reaction injection molding system to be of use with aparticular polymer, certain requirements must be met: (1) the individualstreams must be stable and must have a reasonable shelf-life underambient conditions; (2) it must be possible to mix the streamsthoroughly without their setting up in the mixing head; (3) wheninjected into the mold, the materials must set up to a solid systemrapidly; and (4) any additives-fillers, stabilizers, pigments, etc.,must be added before the material sets up. Therefore, the additivesselected must not interfere with the polymerization reaction.

A thermoset homopolymer having high impact strength and high modulus hasbeen described by Klosiewicz in U.S. Pat. No. 4,436,858 and by Leach inU.S. Pat. No. 4,458,037. Characteristics of thermoset polymers includeinsolubility in common solvents such as gasoline, naphtha, chlorinatedhydrocarbons, and aromatics as well as resistance to flow at elevatedtemperatures.

Work has been done on the metathesis copolymerization ofdicyclopentadiene with one or more other monomers to produce solublecopolymers. This copolymer formation has resulted in the production ofunwanted insoluble by-products. U.S. Pat. No. 4,002,815, for instance,which teaches the copolymerization of cyclopentene withdicyclopentadiene, describes an insoluble by-product and suggests thatthe by-product could be a gel of a dicyclopentadiene homopolymer, butdoes not demonstrate that this is the case.

Some other work, usually in an attempt to produce soluble polymers, hasbeen done on the metathesis polymerization of dicyclopentadiene.Japanese unexamined published patent applications KOKAI Nos. 53-92000and 53-111399 disclose soluble polymers of dicyclopentadiene. Severalsyntheses of soluble polymers of dicyclopentadiene have producedinsoluble by-products. Takata et al, J. Chem. Soc. Japan Ind. Chem.Sect., 69, 711 (1966), discloses the production of an insolublepolymerized dicyclopentadiene by-product from the Ziegler-Nattacatalyzed polymerization of dicyclopentadiene; Oshika et al, Bulletin ofthe Chemical Society of Japan, discloses the production of an insolublepolymer when dicyclopentadiene is polymerized with WCl₆, AlEt₃ /TiCl₄ orAlEt₃ /MoCO₅ ; and Dall Asta et al, Die Makromolecular Chemie 130, 153(1969), discloses an insoluble by-product produced when a WCl₆ /AlEt₂ Clcatalyst system is used to form polymerized dicyclopentadiene.

In U.S. Pat. No. 3,627,739 (Devlin), dicyclopentadiene is gelled withunactivated catalyst and then heated for an hour.

Minchak and Minchak et al respectively in U.S. Pat. Nos. 4,002,815 and4,380,617 each disclose polymerization of cycloolefins to form polymerswhich may be isolated by precipitation using an alcohol or by steam orhot water stripping. The polymers produced have inherent viscositiesfrom about 0.1 to about 10 and are greater than 90% soluble in solvent.Minchak in U.S. Pat. No. 4,426,502 discloses bulk polymerization ofcycloolefins by reaction injection molding in less than about 2 minutesusing an organoammonium molybdate or tungstate catalyst.

DeWitt et al in U.S. Pat. No. 4,418,179 discloses impact modification ofcycloolefins by polymerization using an organo-ammonium molybdate ortungstate catalyst in less than 2 minutes using reaction injectionmolding.

Oshika et al in the Bulletin of the Chemical Society of Japan, line 41,pages 211-217 (1968) discloses ring opening polymerization of norborneneand its derivatives by MoCl₅, WCl₆ and ReCl₅ catalysts. Dark crudepolymer is obtained which is dissolved and reprecipitated with methanol.

U.S. Pat. No. 4,002,815 discloses the use of a metathesis-catalystsystem which employs a dialkylaluminum iodide, an alkylaluminum diiodideor a mixture of trialkylaluminum compounds with elemental iodine toproduce substantially gel-free copolymers of cyclopentene anddicyclopentadiene.

U.S. Pat. No. 4,069,376 discloses the use of a three component catalystcomprised of a soluble tungsten compound, a dialkylaluminum chloride oralkylaluminum dichloride, and a dialkylaluminum iodide or alkylaluminumdiiodide to produce substantially gel-free norbornene-dicyclopentadienecopolymers.

U.S. Pat. No. 4,535,097 discloses a cellular crosslinkedpoly(dicyclopentadiene) which is made with a metathesis-catalyst system.The cellular polymer is made by injecting the catalyst system, whichincludes an alkylaluminum activator, into a reaction vessel which ispreheated, preferably to a temperature from about 100° to about 125° C.

STATEMENT OF THE INVENTION

The thermoset cyclopentadiene homopolymer described herein ischaracterized by having a flexural modulus of at least 150,000 psi atambient temperature, a notched Izod impact strength of at least about1.2 ft. lb./in. notch, a plate impact resistance of at least about 5 ft.lb. and a percent swell in toluene of less than about 200%.

DETAILED DESCRIPTION OF THE INVENTION

Dicyclopentadiene can be polymerized in such a manner that the resultingproduct is a thermoset homopolymer having high impact strength and highmodulus. The preferred monomer, is commercially availableendo-dicyclopentadiene (3a,4, 7,7a tetrahydro-4,7-methano-1H-indene).The exo-isomer, while not commercially available, can be used just aswell. The preferred commercially available material has a purity of 96to 97% and should be purified further in order to prevent impuritiesfrom inhibiting the polymerization. The low boiling impurities fractioncan be removed by stripping away several percent of the unsaturated fourto six carbon atom volatiles, i.e., the volatiles distilled below 100°C. at about 90+3 torr absolute pressure. The monomer can then bepurified even further by treatment with an absorbent such as molecularsieves, alumina or silica gel. Additionally, the water content of thestarting material should be below about 100 ppm. The presence of waterinterferes with polymerization by hydrolysis of both the catalyst andthe activator components of the catalyst system. Water can be removed byazeotropic distillation under reduced pressure.

The polymerization of the purified dicyclopentadiene is catalyzed by atwo part metathesis-catalyst system. One part contains a tungstencatalyst, such as a tungsten halide or tungsten oxyhalide, preferablyWCl₆, WOCl₄ or a mixture thereof. The other part contains anorganometallic activator such as tetraalkyl tin or an alkylaluminumcompound. The alkylaluminum compound can be a trialkylaluminum, analkylaluminum dihalide or a dialkylaluminum halide where the alkyl groupcontains one to ten carbon atoms.

The tungsten containing catalyst is usually employed in solution withdicyclopentadiene monomer. The tungsten compound should first besuspended in a small amount of a suitable solvent. The solvent must notbe susceptible to reacting with the tungsten compound. For instance,when a tungsten halide is employed the solvent must not be susceptibleto halogenation. Examples of preferred solvents are benzene, toluene,xylene, chlorobenzene, dichlorobenzene, and trichlorobenzene. Sufficientsolvent should be added so that the tungsten compound concentration isbetween about 0.1 and 1.0 mole per liter of solution.

The tungsten compound can be solubilized by the addition of a smallamount of an alcoholic or a phenolic compound. Phenolic compounds arepreferred. Suitable phenolic compounds include phenol, alkyl phenols,and halogenated phenols, with tert-butyl phenol, tert-octyl phenol andnonyl phenol being most preferred. The preferred molar ratio of tungstencompound/phenolic compound is from about 1:1 to about 1:3. The tungstencompound/phenolic compound solution can be made by adding the phenoliccompound to a tungsten compound/organic solvent slurry, stirring thesolution and then blowing a stream of a dry inert gas through thesolution to remove any hydrogen chloride. Alternatively, a phenolicsalt, such as a lithium or sodium phenoxide, can be added to a tungstencompound/organic solvent slurry, the mixture stirred until essentiallyall the tungsten compound is dissolved, and the precipitated inorganicsalt removed by filtration or centrifugation. All of these steps shouldbe carried out in the absence of moisture and air to preventdeactivation of the catalyst.

To prevent premature polymerization of the tungsten compound/monomersolution, which would occur within a matter of hours, from about 1 toabout 5 moles of a Lewis base or a chelating agent can be added per moleof tungsten compound. Preferred chelants include acetylacetones, alkylacetoacetates, where the alkyl group contains from one to ten carbonatoms; preferred Lewis bases are nitriles and ethers such asbenzonitrile and tetrahydrofuran. The improvement in the stability andshelf-life of the tungsten compound/monomer solution is obtained whetherthe complexing agent is added before or after the phenolic compound.When purified cycloolefin, for example dicyclopentadiene, is added tothis catalyst solution it forms a solution which is stable and has ashelf-life of several months. The other part of the metathesis-catalystsystem comprises the activator, as described above, preferably dissolvedin dicyclopentadiene monomer.

The period of time between mixing of catalyst, activator and monomer andthe exotherm, which indicates the onset of exothermic polymerization isreferred to as the "induction time". If an unmodified activator/monomersolution is mixed with the catalyst/monomer solution, the induction timeis virtually nil and the polymerization will initiate spontaneously andinstantaneously and the polymer can set up in the mixing head. Theinduction time can be increased by adding a reaction rate moderator tothe activator/monomer solution. Ethers, esters, ketones and nitriles areexamples of compounds which can act as moderators for the alkylaluminumcompounds. Ethyl benzoate, butyl ether, or bis(2-methoxyethyl) ether arepreferred. The induction time can be controlled by varying the specificamount of rate moderator used. The preferred ratio of the alkylaluminumto moderator is from about 1:1.5 to about 1:5 on a molar basis.

The induction time is also temperature dependent. As the temperature atwhich the reaction is carried out is increased the induction time willdecrease. Consequently, to keep the induction time controlled at higherreaction temperatures a less active formulation of the metathesiscatalyst system should be used. One way of reformulating the system isby choice of moderator. Other ways will be readily determinable by oneskilled in the art.

What is ultimately required is that when the catalyst system'scomponents are combined, the resulting cycloolefin (for exampledicyclopentadiene) to tungsten compound ratio will be from about 500:1to about 15,000:1 on a molar basis, preferably 2,000:1 and thedicyclopentadiene to alkylaluminum ratio will be from about 100:1 toabout 2000:1 on a molar basis, preferably about 200:1 to about 500:1. Toillustrate a preferred combination: sufficient dicyclopentadiene isadded to a 0.5 molar tungsten containing catalyst solution prepared asdescribed above, so that the final tungsten compound concentration is0.007 molar. This corresponds to a dicyclopentadiene to tungstencompound ratio of 1000:1. Sufficient dicyclopentadiene is added to thediethylaluminum chloride (Et₂ AlCl) solution, prepared as describedabove, so that the alkylaluminum concentration is 0.048M. Thiscorresponds to a dicyclopentadiene to alkylaluminum ratio of 150:1. Ifthese two streams are mixed in a 1:1 ratio, the final ratio ofdicyclopentadiene to tungsten compound will be 2000:1, the final ratioof dicyclopentadiene to alkylaluminum will be 300:1 and the final ratioof tungsten compound to alkylaluminum will be about 1:7. The illustratedcombination is not the lowest catalyst level at which moldings can bemade, but it is a practical level that provides for excess catalyst ifimpurities in the system consume some of the catalyst components. Ahigher alkylaluminum level will not only increase costs and residualchlorine levels but may result in a less satisfactory cure. Too low atungsten compound concentration results in incomplete conversion. A widerange of alkylaluminum activator to tungsten catalyst formulationsproduce substantially crosslinked polymer products which have goodout-of-mold properties such as tear resistance, stiffness, residualodor, and surface properties.

In a preferred synthesis, the polymerized dicyclopentadiene is made andmolded via the reaction injection molding process. The two parts of themetathesis catalyst system are each mixed with dicyclopentadiene, toform stable solutions which are placed in separate vessels. Thesevessels provide the source for separate streams. The two streams arecombined in the mixing head of the reaction injection molding machineand then injected into a warm mold where they quickly polymerize into asolid, infusible mass. The invention is not intended to be limited tosystems employing two streams each containing monomer. It will beobvious to one skilled in the art that there may be situations where itis desirable to have monomer incorporated in just one stream or toemploy more than two streams where the additional streams containmonomer and/or additives.

These reaction streams are completely compatible with conventionalreaction injection molding equipment. Metathesis-catalyzedpolymerizations are known to be inhibited by oxygen so it is necessaryto store the components under an inert gas but, surprisingly, it is notnecessary to blanket the mold with an inert gas. Effective turbulentmixing is easy to achieve in the mixing head because the processinvolves low viscosity, low molecular weight, rapidly diffusingcomponents. Typically the mixing heads have orifices about 0.032 inch indiameter and a jet velocity of about 400 ft./sec. After being combined,the mixture is injected into a mold maintained at about 35° to 100° C.,preferably 50° to 70° C. The mold pressure is in the range of about 10to 50 psi. A rapid exothermic reaction occurs as thepoly(dicyclopentadiene) sets up. The mold can be opened in as little as20 to 30 seconds after the combined streams have been injected. In thisshort time heat removal is not complete and the polymer is hot andflexible. The polymer releases readily from the mold and can be removedfrom the mold immediately while hot or after cooling. After the polymerhas cooled it will become a rigid solid. The total cycle time may be aslow as 0.5 minute.

The substantially crosslinked dicyclopentadiene polymer product has aflexural modulus of at least about 150,000 psi, a notched Izod impactresistance of at least about 1.2 ft. lb./in. notch and a plate impactstrength of at least about 5 ft. lbs. and resistance to flow attemperatures up to at least 350° C. It is at least 85% and, morecommonly, at least 95% insoluble in common solvents such as gasoline,naphthas, chlorinated hydrocarbons and aromatics.

An important property of the thermoset polymer, which gives rise to thecited desirable characteristics, is the extent to which it iscrosslinked. An indication of the extent of crosslinking is provided bythe polymer's swell value. Gel and swell are determined by a modifiedversion of ASTM D-3616. The measurement is made after the polymer isimmersed in refluxing toluene until equilibrium is reached. Percentswell is defined as swollen polymer weight minus initial polymer weight,divided by initial polymer weight times one hundred. It has been foundthat the polymerized cycloolefins of this invention have a swell valueof less than about two hundred percent.

Various additives can be included to modify the properties ofcycloolefin polymer product of the invention. Possible additives includefillers, reinforcing fillers, pigments, antioxidants, light stabilizers,plasticizers and polymeric modifiers. Because of the rapidpolymerization time the additives must be incorporated before thedicyclopentadiene monomer sets up in the mold. It is often desirablethat the additives be combined with one or both of the reactant streamsbefore being injected into the mold. Fillers can also be charged to themold cavity, prior to charging the reaction streams, if the fillers aresuch that the reaction stream can readily flow around them to fill theremaining void space in the mold. It is essential that the additives notadversely affect catalytic activity.

One class of possible additives is reinforcing agents or fillers. Theseare compounds which can increase the polymer's flexural modulus withonly a small sacrifice in impact resistance. Possible fillers includeglass, wollastonite, mica, carbon black, talc, and calcium carbonate. Itis surprising that, in spite of the highly polar nature of the surfacesof some of these fillers, they can be added without appreciablyadversely affecting the polymerization rate. As much as 75% by weight ofadditives based on the final product weight can be incorporated. Theaddition of fillers which have modified surface properties isparticularly advantageous. The exact amount of a filler to be used in aparticular situation will be easily determinable and will depend on thepreferences of the practitioner. The addition of fillers also serves todecrease the mold shrinkage of the product. After a short post cure at150° to 200° C. an unfilled product will shrink from about 3.0 to about3.5% whereas adding 20 to 25 wt. % filler will decrease the shrinkage to1.5 to 2% and adding 33 wt. % filler will further decrease shrinkage toabout 1%.

Where the filler includes fine particles of a material which issubstantially chemically inert in the polymerization reaction, thismaterial is believed to act as a heat sink to absorb the exothermic heatof polymerization. In the presence of an effective amount (for example10% by weight, of evenly distributed 1/16 inch long milled glass fibersor wollastonite particles) of chemically inert heat sink material themaximum temperature of polymerization is lowered. This is believed toextend the active life of the catalyst so that less percent residualmonomer is left in the poly(dicyclopentadiene) product.

Similarly, low residual monomer polymer products are obtained bycontrolled reaction of cycloolefin monomer using tungsten compoundcatalyst and dialkylaluminum chloride activator in an activator tocatalyst ratio within the range of from about 2.5:1 to about 6:1. Morepreferably, the activator to catalyst ratio is from 2.5:1 to about 4:1.Most preferably, the activator to catalyst ratio is from about 3:1 toabout 3.5:1 to obtain a polymer product having from about 0.3 to about2.0% by weight residual monomer.

Flame retardant additives may be added to one or more of the monomerfeed streams to form polymers which are resistant to burning. Forexample, on a weight basis a flame retardant mixture of 17 parts ofN,N'-ethylene-bis-tetrabromophthalimide, 7 parts Sb₂ O₃ and 8 parts NH₄BF₄ as the flame retardant mixture per 100 parts of dicyclopentadieneimparts a V-0 rating in the UL-94V burn test where UL is an abbreviationfor Underwriters Laboratories when mixed with 0.05 parts WCl₆ and 0.15parts of tri-n-octyl aluminum as described herein to form substantiallycrosslinked polymerized units of dicyclopentadiene. This representseffective flame retardation. The range of weight portions for effectiveflame retardation is from 8 to 20 parts ofN,N'-ethylene-bis-tetrabromophthalimide, from 6 to 15 parts NH₄ BF₄ andfrom 3 to 11 parts Sb₂ O₃ per 100 parts of dicyclopentadiene.

Since polymerized dicyclopentadiene contains some carbon-carbonunsaturation it may be subject to oxidation. The product can beprotected by the incorporation of as much as about 2.0 wt. % of aphenolic or amine antioxidant. Preferred antioxidants include2,6-di-tert-butyl-p-cresol, N,N'-diphenyl-p-phenylene diamine andtetrakis [methylene(3,5-di-t-butyl-4-hydroxy cinnamate)]methane. Whilethe antioxidant can be added to either or both streams, incorporationinto the catalyst/monomer stream is preferred.

The addition of an elastomer can increase the impact strength of thepolymer 5 to 10 fold with only a slight decrease in flexural modulus.The elastomer can be dissolved in one or both of the dicyclopentadienestreams. The amount of elastomer used is determined by its molecularweight and by the initial viscosity of the streams to which it is added.Amounts within the range of 1 to 10% by weight and preferably 5 to 10%by weight of the total stream can be used without causing an excessiveincrease in solution viscosity. An example of preferred elastomer isstyrene-butadiene rubber made by solution polymerization. The additionof about 6% of this elastomer to a dicyclopentadiene stream increasesthe viscosity to about 300 cps. The streams cannot be so viscous thatadequate mixing of the streams is not possible, but increasing theviscosity to between about 300 cps and 1,000 cps improves the moldfilling characteristics of the combined streams. The elastomer ispreferably added to both dicyclopentadiene streams so that theviscosities of two streams are similar. When the two streams havesimilar viscosities, more uniform mixing is obtained when the streamsare combined. An increase in viscosity also reduced leakage from themold and simplifies the use of fillers by decreasing the setting rate ofsolid filler materials. Useful elastomers can be unsaturated hydrocarbonelastomers such as, e.g., styrene-butadiene rubber, polyisoprene,polybutadiene, natural rubber, styrene-isoprene-styrene triblock rubber,styrene-butadiene-styrene triblock rubber, and ethylene-propylene dieneterpolymers; or saturated such as polyisobutylene and ethylene-propylenecopolymer. It is believed that a saturated elastomer forms asemi-interpenetrating network when present during the polymerization ofa cycloolefin, such as dicyclopentadiene. Unsaturated elastomers arebelieved to form interpenetrating networks with the polymerized units ofcycloolefin, such as dicyclopentadiene, when present during thepolymerization of the monomer. In either case, little or none of theelastomer can be removed by extraction.

For use in forming substantially crosslinked thermoset polymers inreaction injection molding, dicyclopentadiene of high purity isrequired. The degree of purity of the dicyclopentadiene monomer maydetermine whether the polymerization proceeds at all and whether anacceptable polymer is formed if polymerization occurs.

The highest purity commercial grade of monomer, 97% by weightdicyclopentadiene, is unacceptable for polymerization withoutpurification. Ninety-seven percent by weight dicyclopentadiene can bemade acceptable for reaction injection molding use by distillation. Forexample, a column packed with 1-inch Intalox Saddles (10 to 12theoretical trays) provides dicyclopentadiene purification with recoveryof purified dicyclopentadiene of about 70 to 75% because the relativevolatilities of some of the polymerization inhibitors appear to be veryclose to that of dicyclopentadiene. Purified dicyclopentadienesubstantially completely polymerizes in about 3/4 minute or less.Purified dicyclopentadiene is produced by nitrogen sparging 97% byweight dicyclopentadiene followed by treatment with alumina.

Although polymerization inhibitors in crude dicyclopentadiene are stillnot fully identified, suspected contaminants are polar compounds such asepoxides, alcohols, aldehydes, and some other oxygen-containingcompounds. Oxygenated compounds have generally intermediate or highpolarity and are adsorbed on alumina or in zeolites.

The major volatile impurities in the 97% pure commercialdicyclopentadiene are isoprene and cis/trans 1,3-pentadiene, which donot affect the polymerization, but are undesirable for a reactioninjection molding process. The volatile compounds can be removed simplyby stripping.

Adsorption, in both mixing contact and fixed bed (percolation), areused. The contact method consists of mixing the dicyclopentadiene to bepurified with an adsorbent in a container with inert atmosphere undercontrolled time and temperature conditions. Agitation is accomplished byadding a magnetic stirring bar to the container. In the fixed bedmethod, the dicyclopentadiene is purified by passing it through a columnpacked with an adsorbent under controlled flow and temperatureconditions.

One of the most effective adsorbents for dicyclopentadiene purificationsis Linde 10A molecular sieve (Union Carbide Type 13X M.S.). Thisadsorbent rapidly turns to a dark chocolate brown color when 97% byweight dicyclopentadiene is added. Most of the dark color can beextracted from the molecular sieves by acetone or hexane. IR analysesindicated that the color extracts are composed mainly of oxygenatedcompounds and some unsaturated cis-olefin. Activated alumina is alsoeffective in removing catalysis poisons from dicyclopentadiene.

EXAMPLES 1 AND 2

In Example 1 a 0.1M solution of a tungsten containing catalyst solutionis prepared by adding 20 grams of WCl₆ in 60 ml of dry toluene under aN₂ atmosphere and then adding a solution of 8.2 grams of p-tert-butylphenol in 30 ml of toluene. The catalyst solution is sparged overnightwith nitrogen to remove the HCl generated by the reaction of WCl₆ withthe p-tert-butylphenol. In this and in all the following examples,phenol is used as a shorthand for p-tert-butylphenol and for simplicitythe solution is referred to as WCl₆ /phenol. Then a 0.033Mcatalyst/monomer solution is prepared by mixing under nitrogen 10 ml ofdicyclopentadiene, 0.07 ml of benzonitrile and 5 ml of the 0.1M catalystsolution. An activator/monomer solution is prepared by combining, undernitrogen, 8.6 ml of dicyclopentadiene, 0.1 ml of isopropyl ether and0.36 ml of 1.0M diethylaluminum chloride (Et₂ AlCl) indicyclopentadiene.

Polymerization is accomplished by adding 1.1 ml of the 0.033Mcatalyst/monomer solution to 8.9 ml of the activator/monomer solution.Both solutions are initially at 25° C. They are vigorously mixed. Aftera brief induction period a sharp exotherm is observed. A solid,insoluble polymer is formed. The time that elapses until rapidpolymerization begins and the total exotherm of the sample above thestarting temperature are shown in Table 1.

In Example 2 the above procedure is repeated except that 0.36 ml of 1.0MEtAlCl₂ is used in place of Et₂ AlCl to prepare the activator solutionand the reaction is started at 40° C. A solid, insoluble polymer isformed. The results are shown in Table 1.

                  TABLE 1                                                         ______________________________________                                                      Example 1                                                                              Example 2                                              ______________________________________                                        Dicyclopentadiene                                                                               72 mmol    72 mmol                                          WCl.sub.6 /Phenol                                                                             0.036 mmol 0.036 mmol                                         Et.sub.2 AlCl   0.36 mmol  --                                                 EtAlCl.sub.2    --         0.36 mmol                                          Benzonitrile    0.04 mmol  0.04 mmol                                          Isopropyl Ether 0.72 mmol  0.72 mmol                                          Initial Temperature                                                                            25° C.                                                                            40° C.                                     Time to Exotherm                                                                              15 sec.    445 sec.                                           Exotherm        122° C.                                                                           147° C.                                     ______________________________________                                    

EXAMPLES 3-8

In Examples 3 through 8 the procedure described in Example 1 is repeatedexcept that different moderators are added to the activator/monomersolution. In each example the ratio of moles of moderator to moles ofEt₂ AlCl is held constant at 2:1. In Example 3, di-n-butyl ether isadded while in Example 4, diisopropyl ether is used. In Example 5, ethylbenzoate is used while in Example 6, phenylethyl acetate is added. InExample 7, diisopropyl ketone is added. Lastly, in Example 8,tetrahydrofuran is added. In each example, the initial temperature is25° C. (+1° C.). Example 8 is the only case where a solid insolublepolymer is not obtained. The results are listed in Table 2.

                                      TABLE 2                                     __________________________________________________________________________              Example 3                                                                            Example 4                                                                            Example 5                                                                            Example 6                                                                            Example 7                                                                            Example 8                        __________________________________________________________________________    Dicyclopentadiene                                                                         72 mmol                                                                              72 mmol                                                                              72 mmol                                                                              72 mmol                                                                              72 mmol                                                                              72 mmol                        WCl.sub.6 /Phenol                                                                       0.036 mmol                                                                           0.036 mmol                                                                           0.036 mmol                                                                           0.036 mmol                                                                           0.036 mmol                                                                           0.036 mmol                       Et.sub.2 AlCl                                                                           0.36 mmol                                                                            0.36 mmol                                                                            0.36 mmol                                                                            0.36 mmol                                                                            0.36 mmol                                                                            0.36 mmol                        Di-n-butyl ether                                                                        0.72 mmol                                                                            --     --     --     --     --                               Diisopropyl ether                                                                       --     0.72 mmol                                                                            --     --     --     --                               Ethyl benzoate                                                                          --     --     0.72 mmol                                                                            --     --     --                               Phenyl ethyl acetate                                                                    --     --     --     0.72 mmol                                                                            --     --                               Diisopropyl ketone                                                                      --     --     --     --     0.72 mmol                                                                            --                               Tetrahydrofuran                                                                         --     --     --     --     --     0.72 mmol                        Benzonitrile                                                                            0.04 mmol                                                                            0.04 mmol                                                                            0.04 mmol                                                                            0.04 mmol                                                                            0.04 mmol                                                                            0.04 mmol                        Time to Exotherm                                                                        42 sec.                                                                              15 sec.                                                                              60 sec.                                                                              282 sec.                                                                             160 sec.                                                                             no rxn.                          Exotherm  153° C.                                                                       122° C.                                                                       155° C.                                                                       157° C.                                                                       147° C.                                                                       --                               __________________________________________________________________________

EXAMPLES 9-12

In Examples 9 through 12 the activator to catalyst ratios are varied. InExample 9, 0.88 ml of catalyst/monomer solution, described in Example 1is added to 7.1 ml of dicyclopentadiene containing sufficient Et₂ AlCland di-n-butyl ether to give the composition listed in Table 3. InExample 10, 0.44 ml of the same catalyst/monomer solution as used inExample 9 is added to 7.5 ml of the same activator/monomer solution usedin Example 9, to give the final composition listed in Table 5. InExample 11, 4.0 ml of a catalyst/monomer solution prepared by mixing 20ml of dicyclopentadiene with 1.5 ml of a 0.1M WCl₆ /phenol solution, ismixed with 4.0 ml of an activator/monomer solution. In this activatorsolution there is sufficient Et₂ AlCl to give a dicyclopentadiene toalkylaluminum ratio of 100:1 and sufficient di-n-butyl ether to give adi-n-butyl ether to aluminum ratio of 2:1. In Example 12, 4.0 ml of thecatalyst/monomer solution used in Example 11 is mixed with 2.0 ml ofdicyclopentadiene and 2.0 ml of the activator/monomer solution used inExample 11. In each case a solid, insoluble polymer is formed. Theresults of these reactions showing a variation in the exotherms due tovariations in the Al/W ratio are listed in Table 3.

                                      TABLE 3                                     __________________________________________________________________________               Example 9                                                                            Example 10                                                                           Example 11                                                                           Example 12                                    __________________________________________________________________________    Dicyclopentadiene                                                                        57.6 mmol                                                                            57.6 mmol                                                                            57.6 mmol                                                                             57.6 mmol                                    WCl.sub.6 /Phenol                                                                        0.029 mmol                                                                           0.0145 mmol                                                                          0.029 mmol                                                                           0.029 mmol                                    Et.sub.2 AlCl                                                                            0.29 mmol                                                                            0.29 mmol                                                                            0.29 mmol                                                                            0.145 mmol                                    Di-n-butyl ether                                                                         0.58 mmol                                                                            0.58 mmol                                                                            0.58 mmol                                                                             0.29 mmol                                    Benzonitrile                                                                             0.033 mmol                                                                           0.016 mmol                                                                           0.033 mmol                                                                           0.033 mmol                                    Dicyclopentadiene/Al                                                                      200    200    200    400                                          Dicyclopentadiene/W                                                                      2000   4000   2000   2000                                          Al/W       10/1   20/1   10/1   5/1                                           Time to Exotherm                                                                         50 sec.                                                                              48 sec.                                                                              33 sec.                                                                              43 sec.                                       Exotherm   153° C.                                                                       120° C.                                                                       145° C.                                                                       168° C.                                Percentage residual                                                                      3.0    4.7    3.0    1.5                                           dicyclopentadiene in                                                          polymer product                                                               __________________________________________________________________________

EXAMPLES 13-15

In Examples 14-15 a small amount of a polar material is added to thecatalyst/monomer solution in order to illustrate the effect of polarmaterial on shelf-life. In Example 13, a catalyst/monomer solution isprepared by adding 2.0 ml of a 0.1M tungsten containing catalystsolution, as described in Example 1, to 20 ml of dicyclopentadiene in anitrogen purged tube. This mixture gelled to a non-flowing materialwithin 24 hours. In Example 14, the same procedure is carried out exceptthat 0.03 ml of benzonitrile is added, giving a final benzonitrile totungsten halide ratio of 1.5:1. This mixture does not gel and iscatalytically active after 4 weeks. Example 15 illustrates the resultwhen tetrahydrofuran is added to give a tetrahydrofuran to tungstenhalide ratio of 1.5:1. Again, a greatly improved storage stability isobserved. The results are listed in Table 4.

                  TABLE 4                                                         ______________________________________                                                   Example 13                                                                            Example 14 Example 15                                      ______________________________________                                        Dicyclopentadiene                                                                          130 mmol  130 mmol   130 mmol                                    WCl.sub.6 /Phenol                                                                           0.2 mmol 0.2 mmol   0.2 mmol                                    Benzonitrile --        0.3 mmol   --                                          Tetrahydrofuran                                                                            --        --         0.3 mmol                                    Condition after 24 hrs.                                                                    gelled    low viscosity                                                                            low viscosity                               Condition after 4 wks.                                                                     gelled    low viscosity                                                                            low viscosity                               Activity after 4 wks.                                                                      gelled    acceptable acceptable                                  ______________________________________                                    

EXAMPLES 16-18

In Examples 16-18, the concentration of di-n-butyl ether incorporatedinto the activator/monomer solution to serve as a moderator is varied.In Example 16, the procedure used in Example 1, is followed with theexception that 0.078 ml of n-butyl ether is substituted for thediisopropyl ether. This gives a final ratio of di-n-butyl ether toalkylaluminum of 1.5:1. In Example 17, the procedure is repeated exceptthat 0.156 ml of di-n-butyl ether is added, giving a final ether/Alratio of 3:1. In Example 18, sufficient di-n-butyl ether is added tobring the final ether to alkylaluminum ratio to 5:1. All the reactionsin Table 3 are initiated at 25° C. In each case a solid, insolublepolymer is formed. The results of the reactions are listed in Table 5.

                  TABLE 5                                                         ______________________________________                                                  Example 16                                                                             Example 17 Example 18                                      ______________________________________                                        Dicyclopentadiene                                                                         57.6 mmol  57.6 mmol  57.6 mmol                                   WCl.sub.6 /Phenol                                                                         0.029 mmol 0.029 mmol 0.029 mmol                                  Et.sub.2 AlCl                                                                             0.29 mmol  0.29 mmol  0.29 mmol                                   Di-n-butyl ether                                                                          0.43 mmol  0.86 mmol  1.45 mmol                                   Benzonitrile                                                                              0.033 mmol 0.033 mmol 0.033 mmol                                  Ether/Al    1.5        3.0        5.0                                         Time to Exotherm                                                                          36 sec.    55 sec.    75 sec.                                     Exotherm    150° C.                                                                           158° C.                                                                           159° C.                              ______________________________________                                    

EXAMPLES 19-21

In Examples 19-21, the level of Et₂ AlCl used in the polymerization ofdicyclopentadiene are varied. In Example 19, 18.5 ml ofdicyclopentadiene was mixed under N₂ with 1.5 ml of a 1.0M solution ofEt₂ AlCl in dicyclopentadiene and with 0.55 ml of di-n-butyl ether. Thenin a N₂ purged tube 8.9 ml of this activator/monomer solution is mixedwith 1.1 ml of a catalyst/monomer solution as described in Example 1. InExample 20, 4.5 ml of the activator/monomer solution used in Example 19is combined with 4.4 ml of dicyclopentadiene and 1.1 ml of thecatalyst/monomer solution used in Example 20. In Example 21, 2.5 ml ofthe activator/monomer solution used in Example 19 is combined under N₂with 6.4 ml of dicyclopentadiene and 1.1 ml of the catalyst/monomersolution used in Example 19. The final compositions of these reactionmixtures are listed in Table 6. All reactions are initiated at 25° C.

                  TABLE 6                                                         ______________________________________                                                  Example 19                                                                             Example 20 Example 21                                      ______________________________________                                        Dicyclopentadiene                                                                           72 mmol    72 mmol    72 mmol                                   WCl.sub.6 /Phenol                                                                         0.036 mmol 0.036 mmol 0.036 mmol                                  Et.sub.2 AlCl                                                                             0.72 mmol  0.36 mmol  0.20 mmol                                   Di-n-butyl ether                                                                          1.44 mmol  0.72 mmol  0.40 mmol                                   Benzonitrile                                                                              0.04 mmol  0.04 mmol  0.04 mmol                                   Dicyclopenta-                                                                             100        200        360                                         diene/Al                                                                      Di-n-butyl ether/Al                                                                       2/1        2/1        2/1                                         Time to Exotherm                                                                          40 sec.    55 sec.    144 sec.                                    Exotherm    150° C.                                                                           151° C.                                                                           145° C.                              ______________________________________                                    

EXAMPLES 22-25

The effect of impurities on the catalyst system is illustrated inExamples 22 through 25. In Example 22, a 0.007M solution of WCL₆ /phenolin dicyclopentadiene is prepared by mixing under nitrogen 150 ml ofdicyclopentadiene with 10.8 ml of a 0.1M WCL₆ /phenol solution intoluene and 0.11 ml of benzonitrile. Then 3.0 ml of this solution ismixed under nitrogen with 3 ml of a dicyclopentadiene solutioncontaining AlEt₂ Cl at a level dicyclopentadiene to alkylaluminum of150:1 and di-n-butyl ether at a level of ether to alkylaluminum of1.5:1.

In Example 23, a 10 ml sample of the catalyst/monomer solution used inExample 22 is mixed with an impurity, 0.036 mmol of H₂ O, added as adispersion in dicyclopentadiene. One and one-half hours later, 3 ml ofthis mixture is mixed under nitrogen with 3.01 of the activator/monomersolution described in Example 22. The reaction is repeated this timecombining the activator/monomer solution with the catalyst/monomersolution 18 hours after the H₂ O had been added.

Example 24 is done in the same manner as Example 23 with the exceptionthat 0.036 mmol of tert-butyl hydroperoxide is added to a second 10 mlsample of the catalyst solution rather than H₂ O. The reactivity of theresultant mixture is checked 11/2 and 18 hours after the addition of theimpurity. Example 25 is carried out in the same manner with theexception that 0.072 mmol of di-tert-butylperoxide is the impurity addedinitially to 10 ml sample of the catalyst/monomer solution. In everycase a solid, insoluble polymer is formed.

                                      TABLE 7                                     __________________________________________________________________________                 Example 22                                                                           Example 23                                                                           Example 24                                                                           Example 25                                  __________________________________________________________________________    Dicyclopentadiene                                                                            43 mmol                                                                              43 mmol                                                                              43 mmol                                                                              43 mmol                                   WCl.sub.6 /Phenol                                                                          0.021 mmol                                                                           0.021 mmol                                                                           0.021 mmol                                                                           0.021 mmol                                  H.sub.2 O    --     0.01 mmol                                                                            --     --                                          tert-butyl-hydroperoxide                                                                   --     --     0.01 mmol                                                                            --                                          Di-tert-butyl-peroxide                                                                     --     --     --     0.02 mmol                                   Et.sub.2 AlCl                                                                              0.14 mmol                                                                            0.14 mmol                                                                            0.14 mmol                                                                            0.14 mmol                                   Added Impurity/W                                                                           0      0.5/1  0.5/1  1/1                                         Induction time after 11/2 hrs.                                                             31 sec.                                                                              50 sec.                                                                               98 sec.                                                                             33 sec.                                     Exotherm after 11/2 hrs.                                                                   173° C.                                                                       171° C.                                                                       168° C.                                                                       171° C.                              Induction time after 24 hrs.                                                               36 sec.                                                                              98 sec.                                                                              266 sec.                                                                             73 sec.                                     Exotherm after 24 hrs.                                                                     170° C.                                                                       170° C.                                                                       155° C.                                                                       169° C.                              __________________________________________________________________________

EXAMPLES 26-33

In each of Examples 26-33, polymerized dicyclopentadiene is made byreaction injection molding processing using a standard reactioninjection molding machine. The following description illustrates theprocedure for molding. First the desired amount of catalyst mixture andactivator dicyclopentadiene is charged to two 2 gallon tanks. The tanksare located on different sides of the reaction injection moldingmachine: the tank on the A side is the one to which the activatormixture is added and the tank on the B side is the one to which thecatalyst solution is added. If desired, rubber and/or organic resins areadded as a predissolved solution in dicyclopentadiene. Also solidfillers are added, if desired.

The tanks are then closed off and placed under a nitrogen atmosphere.Sufficient Et₂ AlCl is added to the activator solution feed tank (the Atank) to bring the alkylaluminum concentration to 0.048M and sufficientdi-n-butyl ether to achieve an ether to alkylaluminum ratio of 1.5:1.Sufficient WCl₆ /phenol is added to bring the concentration of thecatalyst in the catalyst side (B side) to 0.007M. The catalyst solutionis prepared as a 0.1M solution in toluene. All transfers are done in away to preclude the entrance of oxygen or moisture into the system. Thesolution are continuously thoroughly blended in their respective tanks.

The mixing of the activator solution (A stream) and the catalystsolution (B stream) is accomplished using a standard impingement typereaction injection molding mixhead. The ratio of the activator/monomersolution mixed with catalyst/monomer solution is 1:1. The impingementmixing is accomplished by passing both the solutions through orifices0.032" in diameter at a flow rate approximately 80 ml/sec. This requirespumping pressure of approximately 1000 psi.

The resulting mixture flows directly into a mold heated between 50° C.and 60° C. The mold is made of aluminum and is chrome plated. The moldhas a flat cavity which forms a plaque sample 10"×10"×1/8" thick. Aclamping force of 1.5 tons is used to keep the mold closed. The finishedsamples are removed at various times after mold filling ends.

In Example 26, the outlined molding procedure is followed where there isadded 10 wt. % added styrene-butadiene-styrene rubber (Kraton no. 1102manufactured by Shell Chemical Co). The sample is removed from the moldafter 2 minutes. In Example 27 a material of the same composition asExample 26 is produced. This time the mold is opened 30 seconds afterthe combined streams are injected. The surface features of Example 27are noticably better than those of Example 26. In Example 28, 10 wt. %of a thermally polymerized dicyclopentadiene resin is added in additionto both the catalyst/monomer and the activator/monomer solutions inaddition to the styrene-butadiene-styrene rubber.

Various inorganic fillers are incorporated into the dicyclopentadienepolymer by adding equal amounts to both the catalyst/monomer and theactivator/monomer solutions. In Example 29, samples are made containing33 wt. % 1/8" milled glass (P117B grade of Owens Corning Co.). Thesesamples are made by initially slurrying the glass into both solutions ofthe catalyst/monomer and the activator/monomer. Otherwise, thesesolutions are identical to those used in Example 28. In Example 30 acomposition consisting of 10 wt % wollastonite is made by adding thefiller to a formulation identical to that described in Example 28. InExample 31 the same procedure is followed as in Example 30 except that a33 wt % level of wollastonite is employed. In Example 32, 25 wt %wollastonite is added to the formulation described in Example 27. Ineach case a solid, insoluble polymer is formed. Representativeproperties of Examples 26-32 are listed in Tables 8 and 8A.

Example 33 is a reaction injection molding processedpoly(dicyclopentadiene) made without any rubber additives.

                                      TABLE 8                                     __________________________________________________________________________                   Example 26                                                                          Example 27                                                                          Example 28                                                                          Example 29                                                                          Example 30                                                                          Example 31                                                                          Example                                                                             Example              __________________________________________________________________________                                                             33                   Resin Composition                                                             % Cyclopentadiene resin                                                                      --    --    10    10    10    10    --    --                   % Kraton 1102  10    10    10    10    10    10    10    --                   % Dicyclopentadiene                                                                          90    90    80    80    80    80    90    100                  Filler Composition                                                            wt % 1/8" milled glass                                                                       --    --    --    33    --    --    --    --                   wt % wollastonile                                                                            --    --    --    --    10    33    25    --                   Tensile Properties                                                            Strength (psi) --     4,860                                                                               5,230                                                                              --     4,700                                                                              --     4,290                                                                               5,050               Modulus (psi)  --    262,000                                                                             257,000                                                                             --    426,000.sup.1                                                                       --    683,000.sup.1                                                                       270,000              Elongation at yield (%)                                                                      --    4.0   4.0   --    3.0   --     2.0  3.4                  Flexural Properties                                                           Strength (psi)  7,400                                                                               8,600                                                                              --     8,200                                                                               9,000                                                                               8,400                                                                               8,300                                                                               8,400               Modulus (psi)  235,000                                                                             250,000                                                                             --    526,000.sup.2                                                                       390,000.sup.2                                                                       670,000.sup.2                                                                       480,000.sup.2                                                                       270,000              Impact Properties                                                             Notched Izod   13.2  10.5  11.0  2.7   2.0   2.9   --    2.3                  (ft. lb./in. notch)                                                           Plate Impact at                                                               5000"/min. (ft. #)                                                             23° C. 21.0  --    --    --    11.2  --    11.3  --                     0° C. 15.7  --    --    --    12.0  --    11.8  --                   -20° C. 12.3  --    --    --    11.9  --    12.7  --                   Heat Deflection Temperature                                                                  --    65°                                                                          64°                                                                          81°                                                                          69°                                                                          --    79°                                                                          60°           at 264 psi (°C.)                                                       Coefficient of Thermal                                                                       --    6.0 × 10.sup.-5                                                               --    3.2 × 10.sup.-5                        Expansion (in/in °F.).sup.2                                            Linear Mold Shrinkage (%).sup.2                                                               2.6  3.5   3.1   1.0                                          Coefficient of Thermal                 5.2 × 10.sup.-5                                                               --    3.8 × 10.sup.-5                                                               --                   Expansion (in/in °F.).sup.1                                            Linear Mold Shrinkage (%).sup.1        1.6   1.0    1.5  --                   Percentage Residual Monomer                                                                   3.0  3.0   3.0   0.03  0.1    0.03  0.08 3.0                  __________________________________________________________________________     .sup.1 Value in the direction parallel to the direction of flow.              .sup.2 Value is the average of the values obtained perpendicular to the       direction of flow and parallel to the direction of flow.                 

EXAMPLE 34

A catalyst component is prepared in the following manner:

In an argon filled glove box, 3.96 g of WCl₆ is weighed into a 10 oz.bottle. The bottle is then capped. In another 10 oz. bottle, 2.21 g (10mmol) of nonylphenol is added. This bottle is then capped and spargedwith nitrogen for 20 minutes. The nonylphenol is then dissolved in 100ml of toluene, and the resulting solution is transferred by cannula tothe bottle containing WCl₆. After marking the solvent level, the bottleis stirred and sparged with nitrogen for one hour. Acetylacetone, 2.0 g(20 mmol) is then added by syringe and the mixture is sparged rapidlyand stirred overnight. Toluene is then added to restore the solventlevel and the resulting solution is divided among ten 4" polyethylenetubes that are capped and sparged. These are stored under nitrogen.

An activator component is prepared in the following manner:

A 4" glass polymerization tube is capped and sparged. 8 ml of toluene issyringed into the tube. 2.0 ml of a 1.8M solution of diethyl aluminumchloride in toluene is added by a syringe. 0.49 g of butyl ether is thenadded by syringe.

The polymerization is accomplished in the following manner:

A 15×125 mm test tube is capped with a rubber stopper and sparged withN₂. The tube is then charged with 5 ml of dicyclopentadiene. 0.19 ml ofthe catalyst component and 0.038 g of butyl ether are added by syringe.Then, 0.15 ml of the activator component was added by syringe and thesample is shaken several times to mix the components. The mixture isallowed to stand and polymerize.

The percent gel swell is determined by the following method:

A 5 g sample of the polymer was broken out of its test tube and slicedinto approximately 1 cm×1.3 cm diameter cylinders. Each slice was thenweighed and placed on a stainless steel wire. The wire and sample arehung in about 50 ml of toluene in a 1 liter round bottom flask and thetoluene is allowed to reflux overnight. After cooling, the samples areremoved from the flask, patted dry, and weighed. Percent swell isdetermined according to the following equation: ##EQU1##

It is found that the sample has a percent swell of 110%.

EXAMPLE 35

The procedure of Example 34 is followed except that anoncycloolefin-solvent-free mixture of WCl₆ and WCl₄ O in a 1:1 ratiostabilized by 2,4-pentanedione is used as the catalyst in place of WCl₆and polymerization is by simultaneously injection of a mixture of halfof the dicyclopentadiene and the catalyst and a mixture of half of thedicyclopentadiene and the activator component into a mold to form a flatplate of substantially crosslinked solid thermoset polymer product. Theprocedure of Example 35 is repeated with the addition of 20% milledglass.

The product polymer of the invention as produced in Example 35 has anunusual balance of high modulus along with low residual monomer and goodimpact properties as shown in Table 9.

The plate impact strength for unfilled material is about 9.6 to 11.8 ft.lbs. This decreases to only about 8.1 to 9.6 ft. lbs. at -29° C. Impactfailure is by ductile break at room temperature and approaches thebrittle/ductile transition region at -29° C. The impact for 20% milledglass-filled material is about 8.1 to 9.6 ft. lbs. at both ambienttemperatures and -29° C. In this case, the low-temperature failure is bybrittle fracture.

In addition to beneficial physical properties, poly(dicyclopentadiene)exhibits excellent paintability characteristics. This is somewhatsurprising considering the hydrophobic nature of the polymer.Formulations to provide flame-retardant properties have also beendeveloped.

                  TABLE 9                                                         ______________________________________                                        Poly(dicyclopentadiene) Properties                                                       Direction          20% Milled                                                 to Flow  Unfilled  Glass.sup.(a)                                   ______________________________________                                        Flexural     Parallel   2,070     2,900                                       modulus, MPa Perpendicular        2,480                                       Flexural     Parallel   62        62-76                                       strength, MPa                                                                              Perpendicular        62                                          Tensile modulus, MPa    1,620                                                 Tensile strength, MPa                                                                      Parallel   34        31                                          Tensile elongation, %                                                                      Parallel   80        25                                          Glass transition        90                                                    temperature, °C.                                                       Heat sag, 152 mm OH,                                                                       Parallel   61        10-20                                       1 hr., 135° C., mm                                                                  Perpendicular        15-30                                       Coefficient of linear                                                                      Parallel   37 × 10.sup.-6                                                                    17 × 10.sup.-6.sup.(b)                expansion,   Perpendicular        34 × 10.sup.-6.sup.(b)                mm/mm/°C.                                                              Mold shrinkage,                                                                            Parallel   0.035     0.008                                       cm/cm        Perpendicular        0.021                                       Plate Impact                                                                  Resistance, ft. lbs.                                                           23° C.          9.6-11.8  8.1-9.6                                     -29° C.          8.1-9.6   8.1-9.6                                     Flash Point:                                                                  Catalyst mixture with   101       101                                         dicyclopentadiene                                                             Activator mixture       100       100                                         with dicyclopentadiene                                                        ______________________________________                                         .sup.(a) 1/16 in. OCF 737.                                                    .sup.(b) Retained on recycle.                                            

What I claim is:
 1. A substantially crosslinked thermoset polymercomprising polymerized units of dicyclopentadiene, said homopolymerbeing characterized as having a flexural modulus of at least 150,000 psiat ambient temperature, a notched Izod impact strength of at least about1.2 ft. lb./in. notch, a plate impact strength at 23° C. of at leastabout 5 ft. lb. and a percent swell in toluene of less than 200%.